In the production of lipstick mines, different waxes and additives are mixed. For this purpose, the waxes and additives are converted into a flowable state by heating prior to mixing. The mixed waxes and additives can also be referred to as pasty mass. The pasty mass is, after mixing, filled into a mold and cooled in this mold to solidify in the mold and to create a lipstick mine.
However, cooling of the pasty mass in the mold results in the problem that unevenness is formed on the surface, for example on a free surface. A free surface is in this case any surface of the pasty mass, which is not contacted by the mold or a wall of the mold. The unevenness can also be called a crater because these irregularities are usually more pronounced at the edge of the surface than in the center of the surface.
Processes and devices are known which attempt to melt the surface of the pasty mass in order to prevent a crater from forming by melting, while the remaining pasty mass cools and solidifies in the mold.
For example, U.S. Pat. No. 4,172,113 describes a device in which open molds with the pasty mass contained therein are moved under air nozzles, wherein heated air streams out of the air nozzles. The nozzles are directed vertically downwards and arranged in a row so that the molds pass through a plurality of nozzles during their movement. The nozzles are dimensioned in such a way that the heated air is specifically directed onto the surface of the pasty mass in the molds, which are just below the nozzle. This is intended to ensure that the pasty mass can remain in a flowable state on its surface after casting, while the remaining pasty mass solidifies in the mold so that the formation of a crater is prevented. However, the device shown in U.S. Pat. No. 4,172,113 is not very energy-efficient. On the one hand, a lot of energy is needed to heat the air, and on the other hand much energy is lost by the air stream. Furthermore, the apparatus has the disadvantage that the heated air stream blows the liquid mass out of the mold. This results in a clearly visible contamination of all machinery parts involved in the process.
It is therefore the object to provide a method and an apparatus, which do not have the above-mentioned disadvantages. In particular, with the method and the apparatus, the surface of the pasty mass is to be heated in the mold as energy-efficient as possible without any contamination of the machinery parts.